JP2953479B2 - Resist coating apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist coating apparatus and method useful for manufacturing semiconductors. In recent years, the miniaturization of semiconductors has progressed, and accordingly, the pattern width has become narrower. In the pattern forming step, the excess resist is shaken off by rotating the wafer, so that the resist has a uniform film thickness. At this time, the resist mist and fine particle impurities scattered adhere to the cup surrounding the wafer.
If the resist adheres to the cup in excess of the reference amount, these impurities adhere to the wafer and significantly reduce the quality of the semiconductor. Further, if the resist adheres nonuniformly to the cup, the airflow between the cup and the wafer becomes nonuniform, and the resist film on the wafer cannot be formed in a uniform thickness. In such a case, remove the cup and replace it with a new or washed cup.

[0002]

2. Description of the Related Art In a resist coating apparatus, the number of wafers coated with resist or the time elapsed during resist coating has conventionally been used to determine when to remove a cup and replace it with a washed cup or a new cup. The time spent was used as a criterion for determination and was unconditionally replaced. But,
In this method, a cup that does not need to be replaced may be removed.

In order to control the degree of pressure reduction for exhausting the cup, a flow rate sensor is provided to detect the static pressure flow rate of the exhaust gas, and thereby, a predetermined flow rate is often maintained. In this method, the resist accompanying the exhaust gas sometimes adheres to the flow sensor, which has a disadvantage that the accuracy of the flow detection is reduced.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to optimize the timing of cup replacement and the degree of pressure reduction for exhausting the cup in resist coating.

[0005]

The object of the present invention is to provide a cup 2 surrounding a wafer 1, a motor 3 for rotating the wafer 1, a pump 4 for evacuating the cup 2, and a discharge pipe 5 for flowing a resist down the wafer 1. A weight sensor 7 is provided on the cup 2 to which the resist 6 shaken off from the wafer 1 adheres, and the weight sensor 7 is connected to the sensor 7 and corresponds to the weight increase detected by the sensor 7. A controller 8 for controlling the resist coating operation, a resist coating operating means 9 controlled by the controller 8 to interrupt the resist coating operation when the weight increase of the cup 2 exceeds a reference value, When the weight increase of the cup 2 changes beyond the reference range,
A resist coating apparatus characterized by comprising exhaust pressure adjusting means 10 for adjusting the degree of pressure reduction by exhausting from the cup 2 in response to a command signal from the controller 7; Then, when the weight increase of the cup 2 to which the resist has adhered exceeds the reference value, the resist coating operation is interrupted, thereby optimizing the replacement time of the cup 2 and increasing the weight corresponding to the number of processed wafers 1. When the value fluctuates beyond the reference range,
The resist coating method is characterized in that the degree of reduced pressure for exhausting the resist is adjusted, and thereby the thickness of the resist is optimized.

[0006]

As shown in FIG. 3, a reference curve in which the weight of resist increases in accordance with the number of processed sheets is empirically set.
When the 00 sheets are reached, the application operation can be stopped, the cup removed and replaced with a washed cup or a new cup. Further, when the actual weight increase curve B shows a higher value than the reference curve A corresponding to the number of processed sheets, the amount of the resist adhering to the cup is increased by increasing the exhaust pressure and increasing the suction of the resist because the resist adheres too much. Decrease. When the value is lower than the reference curve A, there is a region where the amount of resist adhering to the cup is partially small, and the airflow passing therethrough is larger than in other regions. Become. In this case, reduce the exhaust pressure,
Increase the amount of resist attached.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS After a resist having a viscosity of 500 cp flows down from a discharge pipe 5 onto a wafer 1 of a resist coating apparatus shown in FIG. 1, the wafer 1 is discharged at 5,000 rpm while the cup 2 is evacuated to 10 mmH ₂ O.
Spin at pm to shake off excess resist. Thus, a process of applying a resist to the wafer 1 was performed one after another, and the increase in the weight of the cup, that is, the variation in the weight of the applied resist was controlled within a reference range of ± 5 g. Processing of wafer progresses,
The coating treatment was stopped when the weight increase of the cup reached 50 g. The number of processed sheets exceeded the conventional standard value of 500, and 580 sheets could be processed. In each of the obtained wafers 1, the resist film thickness was uniform, and a precise pattern could be formed in a subsequent pattern forming step.

[0008]

According to the present invention, since the cup can be replaced at an appropriate time, the operation rate of the resist coating apparatus can be improved, and the environmental conditions for forming the resist film can be optimized with good reproducibility. it can.

[Brief description of the drawings]

FIG. 1 is a schematic view of a resist coating apparatus according to the present invention.

FIG. 2 is a schematic view of a conventional resist coating apparatus.

FIG. 3 is a graph showing a relationship between an increase in the weight of a cup and the number of coated sheets.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Wafer 2 ... Cup 3 ... Motor 4 ... Exhaust pump 5 ... Discharge pipe 6 ... Resist 7 ... Weight sensor 8 ... Controller 9 ... Resist coating operation means 10 ... Exhaust pressure adjustment means A ... Reference processing curve B ... Reference fluctuation range C: Actual processing curve

Continuation of the front page (56) References JP-A-57-166033 (JP, A) JP-A-64-175032 (JP, A) JP-A-2-34908 (JP, A) JP-A-4-123529 (JP) , A) JP-A-4-322420 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/027

Claims (2)

(57) [Claims] 1. A cup (2) surrounding a wafer (1), a motor (3) for rotating the wafer (1), and a cup (2)
A resist coating device having a pump (4) for evacuating the wafer and a discharge pipe (5) for flowing the resist down to the wafer (1), wherein the resist (6) shaken off from the wafer (1) adheres. (2) a weight sensor (7), a controller (8) connected to the sensor (7) and controlling a resist coating operation in response to the weight increase detected by the sensor (7); (8) a resist coating operation means (9) for interrupting the resist coating operation when the weight increase of the cup (2) exceeds a reference value; and a cup (2) corresponding to the number of processed wafers (1). And (e) exhaust pressure adjusting means (10) for adjusting the degree of decompression due to exhaust from the cup (2) in response to a command signal from the controller (7) when the weight increase fluctuates beyond the reference range. Resist coating apparatus characterized by being configured by including. 2. The apparatus according to claim 1, wherein the resist coating operation is interrupted when the weight increase of the cup having the resist attached thereto exceeds a reference value, whereby the cup is replaced. At the right time, wafers (1)
When the weight increase corresponding to the number of processed sheets fluctuates beyond the reference range, the degree of decompression for exhausting the cup (2) is adjusted,
A resist coating method wherein the thickness of the resist is thereby made uniform.